The present invention relates to the dispensing of sheet material. More specifically, the invention relates to an apparatus for dispensing predetermined lengths of sheet material.
Sheet material dispensers for dispensing, for example, but not by way of limitation, paper towels, generally include a housing, and a supply of sheet material within the housing in the form of individual sheets, folded sheets, festooned sheets, or a roll of sheet material which can be dispensed as individual sheet materials, such as, for example only, paper towels. Roll towel dispensers typically include a mechanism for advancing sheets or unrolling the sheet material roll. In some dispensers, the mechanism includes a lever or a crank for manually dispensing sheet material from the roll, and the dispenser housing often carries a blade for cutting the lengths of sheet material from the roll. Manual contact with a dispenser lever or one or more sheets touched by another user can be a health hazard for a user, especially in certain environments such as, by way of non-limiting example, in hospitals, and so forth.
Further, another disadvantage of sheet dispensers is that the softness and absorbency characteristics of the sheet material, or lack thereof, are limited by the mechanical and/or electrical limitations of the dispenser. That is, the dispenser has a predetermined setting which provides the same amount of sheet material to a user, whether or not the sheet material is a soft, highly absorbent sheet material, or whether the sheet material has a much lower absorbency.
A sheet material which is soft and highly absorbent only requires, for example, about eleven to twelve inches, or less, of sheet material per hand drying even to sufficiently dry a user's hands to the user's satisfaction. A sheet which is not highly absorbent may require fourteen inches, eighteen inches, or more to sufficiently dry a user's hands to the user's satisfaction. When a dispenser is preset to dispense, for example, about twelve inches of sheet material, it may satisfy a user if highly absorbent. However, if the sheet material is low absorbency, it will likely result in the user obtaining at least another twelve (12) inch sheet. This results in waste, higher costs to maintain sheet material in the dispenser, and a greater environmental impact.
Some dispensers allow a change in length of the sheet material dispensed by a manual manipulation of the dispenser prior to the introduction of a new roll of sheet material. A disadvantage with these dispensers is that they require an operator to manually adjust the sheet material length during replacement of a roll. Apart from requiring time, effort and expertise from the operator, there is the risk of human error in the resetting operation.
Accordingly, there remains a need in the art for a sheet material dispenser which automatically dispenses different lengths of sheet material based on characteristics of the sheet material, such as absorbency, and so forth. Desirably, such a sheet material dispenser would recognize the sheet material, and would dispense an appropriate amount in one sheet to satisfy a user's hand drying needs, but limit cost and waste.